Salmon Spawn in Petitcodiac


Salmon spawn in Petitcodiac

By james Foster

Times & Transcript Staff
15 Aug 2013 08:03PM

Farmers know that good seed is one key to producing a good crop, but that also holds true for rebuilding an endangered species of fish.

To that end, within one day of erecting their fish-monitoring net in the Petitcodiac River earlier this week, the Petitcodiac Watershed Alliance recovered two Inner Bay of Fundy Atlantic salmon, and it appears these fish have spawned in the river system, a key step in restoring the unique strain of salmon that once thrived in these waters.

It’s news that has heartened the alliance as well as river watchers who have waited for signs that all of the river’s fish populations would return after the 2010 reopening of the gates under the Moncton-Riverview causeway.

That this is great news for fans of the river and of the salmon is obvious. However, it is tempered by the fact that these are not fish that returned to the river spontaneously; rather, they are two out of hundreds of adult fish taken from a gene bank and placed in a tributary of the Petitcodiac last fall. Still, it’s a big step forward, alliance co-ordinator Susan Linkletter says.

“We put them in there in November, females ready to spawn, and they have spawned,” Linkletter said Friday.

And project workers from the Fort Folly First Nation have also found more than 70 salmon redds in the system. Redds are where the salmon lay their eggs. This suggests that these two salmon are not the only ones — by far — that have spawned in the system, which is even further good news.

The key now is to allow the spawned fish to return to the Bay of Fundy, grow and return to spawn again. Repeat spawners produce far more, and more robust, eggs and have higher success rates at reproducing.

Once the cycle takes root in a big way, there is potential for a self-sustaining population in the river again, just as there was prior to the causeway being built in the late 1960s.

“So the big deal is that these fish are 99 per cent extinct,” Linkletter explained, “and now people have to leave them alone.”

Salmon returns are believed to have numbered up to 9,000 in the Petitcodiac River during peak years, with 2,000 to 3,000 salmon returning annually in the years just prior to the causeway’s construction.

The structure was supposed to have a fish ladder built into it to accommodate the salmon, but it never worked properly.

In just a few years after the causeway was built, commercial salmon landings dropped by two-thirds, and then that season was shut down.

Angling harvest averaged 171 bright and 263 black (spring) salmon per year in 1960-1967 and then declined to 25 bright and 66 spring salmon per year between 1968 and 1978.

The only salmon in the river now are believed to be those put there from the gene bank in an attempt to bring the species back to healthy levels.

Gene bank salmon shouldn’t be confused with hatchery salmon, as these are salmon from the very specific and unique strain of Inner Bay of Fundy salmon that used to thrive in the Petitcodiac. Those fish and their descendants are genetically better predisposed to surviving in the Petitcodiac system, and the evidence of salmon spawning makes researchers and volunteers believe that that is exactly what is happening.

“They actually spawned,” Linkletter said, “and there has been probably hundreds and thousands of eggs now deposited into the river.”

Meanwhile, the fish-counting trap also captured a spawning shad, another milestone event since the shad population had been essentially wiped out in recent decades, and the shad has been one of the species that has been slowest to make a comeback.

“That’s the first time that we’ve seen that since we first put the nets in three years ago,” the biologist said.

It is strongly believed that the disappearance of the shad and the extinction of the dwarf wedge mussel that used to live in the river are directly related, and not only because both vanished at about the same time. After only days in the water, evidence collected from the fish monitoring nets so far this year has raised the hopes of project participants and casual observers alike.

It is noteworthy that the nets cover only a portion of the river, making it quite likely that more of these species are in the river as well but weren’t captured and counted.